Apparatus and methods for a distributed memory system including memory nodes

ABSTRACT

Apparatuses and methods for a distributed memory system including memory nodes are disclosed. An example apparatus includes a processor and a memory system coupled to the processor. The memory system is configured to receive instructions from the processor to access information stored by the memory system. The memory system includes a plurality of memory nodes, wherein each memory node of the plurality of memory nodes is coupled to at least one other memory node of the plurality of memory nodes, and each memory node of the plurality of memory nodes is configured to generate an internal message including instructions for an operation, the internal message to be provided to another memory node of the plurality of memory nodes to perform the operation.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/842,984, filed Mar. 15, 2013 and U.S. Pat. No. 10,089,043 on Oct. 2,2018. The aforementioned application and patent are incorporated hereinby reference, in their entirety, for any purpose.

BACKGROUND OF THE INVENTION

The processing power of computing platforms is increasing with theincrease in the number of cores and the number of threads on computingplatforms. This increase in processing power leads to a correspondingincrease in the demands placed on system memory. For example, read andwrite operations to system memory increase as the core and thread countincrease. There is a risk that memory accesses will become a substantialperformance bottleneck for computing platforms. For example, intraditional computer architectures, the CPU to memory interface may posea significant bottleneck, such as for bulk memory operations. That is, abottleneck may be created as a result of the CPU controlling everytransaction to, from, and within the memory system for performingoperations on information stored by the memory system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an apparatus including, a memory systemaccording to an embodiment of the invention.

FIG. 2 is a block diagram of a memory system according to an embodimentof the invention.

FIG. 3 is a block diagram of a memory node according to an embodiment ofthe invention.

FIG. 4 is a block diagram of an example operation of a memory systemaccording to an embodiment of the invention.

FIG. 5 is a diagram of a linked data structure.

FIG. 6 is a flow diagram of an example operation of a memory systemaccording to an embodiment of the invention.

DETAILED DESCRIPTION

Certain details are set forth below to provide a sufficientunderstanding of embodiments of the invention. However, it will be clearto one skilled in the art that embodiments of the invention may bepracticed without these particular details. Moreover, the particularembodiments of the present invention described herein are provided byway of example and should not be used to limit the scope of theinvention to these particular embodiments. In other instances,well-known circuits, control signals, timing protocols, and softwareoperations have not been shown in detail in order to avoid unnecessarilyobscuring the invention.

FIG. 1 illustrates an apparatus including a processing system 100according to an embodiment of the invention. The processing system 100includes a processor 110 coupled to a memory 120 through a local memorybus 130. As used herein, “processor” may refer to a central processingunit CPU, graphics processing unit GPU, system controller, memorycontroller, etc. The processor 110 may represent one or more processors.The processor 110 may use the memory 120 for storing information; forexample, programs, instructions, and/or data that may be desirable to beaccessed by the Processor 110 quickly. The processing system 100 furtherincludes a memory system 140 with which the processor 110 communicatesover a memory bus 150. The memory system 140 may be used to storerelatively large amounts of information, for example, large sets ofprograms, instructions, and/or other information.

The information stored by the memory system 140 may be accessed by theprocessor 110 providing messages that are received by the memory system140. The messages may include information, for example, instructionsand/or data for the memory system 140. The messages may additionally oralternatively include information related to the source memory node,destination memory, as well as the operation to be performed. The memorysystem 140 may carry out operations according to the instructionsincluded in the messages provided by the processor 110. The memorysystem 140 may provide messages to the processor 110 responsive to themessages received from the processor 110. For example, the memory system140 may receive from the processor 110 a message including instructionsto read information from the memory system 140. Responsive to themessage from the processor 110, the memory system 140 may perform a readoperation and provide a message to the processor 110 including theinformation that was read. In another example, the memory system 140 mayreceive from the processor 110 a message including instructions forwriting information to the memory system 140, and further including theinformation to be written. Responsive to the message from the processor110, the memory system 140 may perform a write operation to write theinformation to memory. The memory system 140 may provide a messageincluding an acknowledgment of completion of the write instructions tothe processor 110. messages including various other types ofinstructions, data, and/or other information may be received andprovided by the memory system 140 and processor 110 as well.

In some embodiments, the memory system 140 may be, or includes, a memorysystem including a plurality of memory nodes. The memory nodes may beconfigured to provide information (e.g., instructions, data, etc.)between the memory nodes, for example, to carry out an operationresponsive to receiving a message from the processor 110. The memorysystem 140 may represent a distributed memory system having a pluralityof memory nodes communicatively coupled together through a communicationnetwork. With such memory systems, instructions for higher level memoryoperations may be available. Such operations may be managed among thenodes of the memory system 140 with little to no involvement by theprocessor 110. A benefit of a memory system 140 as described may be toreduce transactions between the memory system 140 and the processor 110over the memory bus 150, which may be considered a “bottleneck” for theoperability of the processing system 100. Reducing the transactionsbetween the memory system 140 and the processor 110 may result inimproved performance of the processing system 100 because less time maybe devoted by the processor 110 managing memory operations and less timemay be wasted by the processor 110 performing computational operationson information provided by the memory system 140.

FIG. 2 illustrates a memory system 200 according to an embodiment of theinvention. The memory system 200 may be included in the memory system140 of the processing system 100 of FIG. 1. The memory system 200includes a plurality of memory nodes 210(1)-(N). The memory nodes210(1)-(N) may be communicatively coupled together so that a memory nodemay communicate with at least one other memory node of the memory system200. For example, a communication network 220 may be used tocommunicatively couple together the memory nodes 210(1)-(N). In someembodiments, the memory nodes 210(1)-(N) may be configured tocommunicate by exchanging messages (e.g., packets) with another memorynode 210(1)-(N) over the communication network 220. The messagesexchanged between the memory nodes 210(1)-(N) may be implemented usingvarious known or later developed messaging technologies. For example,the memory node 210(1) may be able to provide packets to one, several,or any of the other memory nodes 210(2)-(N) of the memory system 200. Inthis manner, packets may be efficiently provided and received betweenthe memory nodes 210 of the memory system 200. Although communicationbetween the nodes as described herein is made with reference to packets,it will be appreciated other forms of messages may be used withoutdeparting from the scope of the present invention.

The memory nodes 210 may be communicatively coupled through wired and/orwireless communication mediums. Communication between the memory nodes210 may utilize known communication protocols, for example, theTransmission Control Protocol/Internet Protocol (TCP/IP). Where wirelesscommunication is utilized, the memory nodes 210 include wirelesscommunication circuitry suitable for communicating between the memorynodes 210. Likewise, where wired communication is utilized, the memorynodes 210 include wired communication circuitry suitable forcommunicating between the memory nodes 210.

Packets including instructions and/or data may be received from outsideof the memory system 200, for example, from processor 110 as describedwith reference to FIG. 1. The packets are provided to one or more of thememory nodes 210(1)-(N), which perform operations based on theinstructions and/or data. For example, operations may include a readoperation, a write operation, key search, addition and/or deletion ofinformation of a data structure, updating fields in a data structure,etc.

As will be described in more detail below, a memory node 210 may includelocal memory for storing information (e.g., data, instructions, etc.),and may include logic and/or processing capability configured to performcomputational operations responsive to packets it receives. Examples ofcomputational operations may include Boolean logic operations,arithmetic operations, comparison operations, as well as othercomputational operations. A memory node 210 may further include logicand/or memory control capability configured to control operation of thelocal memory, as well as generate packets that may be provided to othermemory nodes 210 or provided externally from the memory system 200, forexample, to processor 110. The packets generated by a memory node 210may include instructions and/or data, which can cause receiving memorynodes 210 to perform operations based on the instructions and/or data.The packets may further include source and destination information forthe memory nodes.

As will be described in more detail below, when a memory node receives apacket, the memory node may perform local operations (e.g., memoryoperations, computational operations, etc.) on information stored bylocal memory of the memory node. Based on the results of the localoperations, the operations may be completed, or in some instances,incomplete. When operations require additional information and/orprocessing outside the memory node, the memory node may rely on anothermemory node of the memory system for the additional information and/orprocessing. For example, the memory node may determine a destinationmemory node for a next operation or operations, determine the source forthe next operation or operations, and generate a packet or packets thatmay include various information, such as information related to thesource memory node, the destination memory, the operation, and/or data.The packet is provided from the memory node to another memory node ormemory nodes.

By exchanging packets between the memory nodes to communicate,transactions between the memory system 200 and a processor 110 may bereduced as operations by the memory nodes 210(1)-(N) may be performed,as previously discussed, based on instructions and/or data included inpackets generated by memory nodes within the memory system 200. Asdescribed herein, “external” packets (which are examples of “external”messages) may be received by the memory system, or provided by thememory system, and “internal” packets (which are examples of “internalmessages”) may be provided between the memory nodes. Internal packetsmay be the same or similar to the external packets. For example, theformat of the internal packets and external packets may be similar. Insome embodiments, the internal packets may be different than externalpackets, for example, the internal packets may include additionalinformation to communicate between the memory nodes, have a differentformat than the external packets, etc.

FIG. 3 illustrates a memory node 300 according to an embodiment of theinvention. The memory node 300 includes a local memory 310 coupled to abus 320. The bus 320 is configured to provide communications between theblocks included in the memory node 300. The local memory 310 may includedifferent types of memory, for example, the local memory 310 may includevolatile memory 310(1) and non-volatile memory 310(2). The local memory310 may be configured to store and provide information associated withthe memory node 300.

A node controller 330 coupled to the bus 320 may be configured tocontrol operations of the memory node 300. The node controller 330, forexample, may provide instructions over the bus 320 to control the localmemory 310 to perform various memory operations, such as to readinformation from the memory or to store information in the memory. Thenode controller 330 may control computational logic that may beconfigured to perform computations on information, such as informationstored in the local memory 310 and/or provided to the memory node 300.The node controller 330 may control a communication interface 340 thatmay be configured to provide communications with the memory node 300,such as communicating with another memory node and/or a processor (e.g.,processor 110). The communication interface 340 is further coupled tothe bus 320, which allows for communication with the local memory 310 aswell. The memory node 300 may be configured to communicate over wiredand/or wireless mediums, including circuitry for such communications.For example, the communication interface 340 may include circuitry thatis configured for wired communication with other memory nodes, and thecommunication interface may alternatively or additionally includecircuitry that is configured for wireless communication with othermemory nodes.

As previously discussed, packets provided to a memory node may includeinformation, such as instructions and data. Responsive to receivingpackets, the node controller 330 may control the local memory 310 and/orthe computational logic 350 to perform memory operations andcomputational operations. For example, a packet received by the memorynode 300 may include instructions to perform a write operation, andfurther include information to be stored in the local memory 310according to the write operation. The node controller 330 may generatecontrol signals for the local memory 310 to store the informationincluded with the packet. In other examples, a packet received by thememory node 300 may include instructions to perform a computationaloperation on information stored by the local memory 310. The nodecontroller 330 may generate control signals for the local memory 310 andthe computational logic 350 to access the information stored in thelocal memory 310 and perform the computational operation. Examples ofcomputational operations may include Boolean logic operations,arithmetic operations, comparison operations, as well as othercomputational operations.

As will be further described below, the node controller 330 may befurther configured to generate packets that may be provided to othermemory nodes, as well as packets that may be provided external to amemory system including the memory node 300. The node controller 330 maydetermine a destination for the packets (e.g., a receiving memory nodeor receiving memory nodes). The destination may be determined based on,for example, the information, the memory operation, or a combination ofboth. The packets generated by the node controller 330 may includeinstructions for other memory nodes to perform operations. The packetsmay alternatively or additionally include information for the othermemory node. Thus, a memory node may locally determine a destinationnode for a packet that is generated internally to the memory system, andthe packet generated may be based on the results of local processing atthe memory node.

Including the memory node 300 in a memory system, such as the memorysystem 200, may reduce the number of memory transactions with the memorysystem. Instructions issued by the processor in effect go to theinformation (stored in the memory system), rather than having theinformation come to the processor, which may place significantoperational burden on the processor while leaving memory systembandwidth unutilized. As a result of having a memory system that may beconfigured to control operations internally among memory nodes and withless intervention by the processor, operational efficiency of aprocessing system may be improved.

FIG. 4 illustrates a diagram of an example operation of a memory systemaccording to an embodiment of the invention. The example of FIG. 4 isrelated to receipt by a memory system according to an embodiment of theinvention (e.g., the memory system 200 of FIG. 2) of a packet includinga memory request. The packet may be received from, for example, aprocessor, such as the processor 110 of FIG. 1, and will be referred toas an “external” packet. In the example of FIG. 4, the memory request isfor the receiving memory system to find and provide information relatedto a “key” identified in the external packet.

The external packet is received by memory node 210(1) to requestinformation related to the key, as illustrated in FIG. 4 by arrow 402. Anode controller of the memory node 210(1) may perform operationsresponsive to the external packet, for example, operations to access theinformation stored in local memory and determine whether informationrelated to the key is present within local memory of the memory node210(1). For example, the node controller of the memory node 210(1) mayprovide memory commands to the local memory of the memory node 210(1) toprovide stored information from the local memory for comparison bycomputational logic to determine whether any information satisfying therequest is stored in the local memory of the memory node 210(1), thatis, whether any stored information matches the key.

In addition to the operations performed by the node controller andcomputational logic of the memory node 210(1), the memory node 210(1)(e.g., a “sending” memory node) determines that packets (e.g., “internalpackets) should be provided to other memory nodes (e.g., “receiving”memory nodes) of the memory system 200. The node controller of thememory node 210(1) determines the receiving nodes for the internalpackets, and as shown in FIG. 4, the memory node 210(1) providesinternal packets to memory nodes 210(3), 210(5), and 210(10), asillustrated in FIG. 4 by the arrows 410, 412, and 414, to continue therequest for information.

The internal packets provided by the memory node 210(1) may includeinstructions for requests for information, for example, to continue thesearch for information matching the key that may be stored by the localmemory of the other memory nodes. The internal packets may alternativelyor additionally include information, for example, information identifiedduring the operations performed by the sending memory node as matchingthe key. The internal packet provided by the memory node 210(1) mayinclude some or all of the information (e.g., instructions, data, etc.)from the external packet it received (e.g., represented by arrow 402).The internal packet provided by the memory node 210(1) may includeinformation that are not included in the external packet the memory node210(1) received. For example, the internal packet may includeinformation generated by the node controller and the computational logicof the memory node 210(1) that was not included in the external packet.The information may assist the receiving memory nodes in performingoperations, for example, to satisfy the request for informationassociated with the external packet.

The receipt of an internal packet from a sending memory node, theperformance of an operation responsive to the internal packet, and/orproviding an internal packet by the receiving memory node to anothermemory node (e.g., the “receiving” memory node becomes a new “sending”memory node) may continue throughout the memory system 200. For example,responsive to the internal packet provided by the memory node 210(1) tothe memory node 210(3) (e.g., arrow 410), the node controller andcomputational logic of the memory node 210(3) may perform operationssuch as searching its local memory for information satisfying theinitial request to the memory 200. The node controller of the memorynode 210(3) may additionally generate additional internal packets, whichmay include information, for example, instructions related to theinitial request to the memory 200 and/or data identified in the localmemory of the memory node 210(3) satisfying the initial request. Theinternal packets are provided by the memory node 210(3) to memory nodes210(4) and 210(6) (e.g., as represented by arrows 416 and 418,respectively).

As further illustrated in FIG. 4, the internal packet from the memorynode 210(3) to the memory node 210(4) results in the generation ofanother internal packet by the memory node 210(4) that is provided tothe memory node 210(7) (as represented by arrow 424), and in response,the memory node 210(7) generates and provides an internal packet to thememory node 210(6) (as represented by arrow 426). Likewise, the memorynode 210(10), which received an internal packet from the memory node210(1) (as represented by the arrow 414) generates and provides aninternal packet that is provided to the memory node 210(6) (asrepresented by the arrow 422). The memory node 210(5), which received aninternal packet from the memory node 210(1) (as represented by the arrow412) generates and provides an internal packet that is provided to thememory node 210(6) (as represented by the arrow 420).

As previously discussed, receipt of an internal packet from a sendingmemory node may cause a receiving memory node to perform operationsrelated to instructions and/or data included in the internal packetreceived, for example, searching the local memory of the receivingmemory node for information. Additionally, the receiving memory node maygenerate an internal packet that includes instructions and/or data to beprovided to another memory node. The internal packet that is generatedby the receiving memory node (which then becomes a sending memory node)may include instructions and/or data for the new receiving memory node.

A memory node 210(6) receives internal packets from memory nodes 210(3),210(5), 210(7), and 210(10), as illustrated in FIG. 4 by arrows 418,420, 426, and 422, respectively. The internal packets from the memorynodes may include information identified by the node controller andcomputational logic of the respective memory nodes that satisfy memoryrequests included in the respective internal packet the memory nodereceived from a sending memory node. For example, the internal packetsfrom the memory nodes (e.g., 210(3), 210(5), 210(7), and 210(10)) mayinclude instructions for the memory node to perform operations, forexample, related to the initial request for information associated withthe external packet received by the memory system 200 (e.g., representedin FIG. 4 by arrow 402). In the example of FIG. 4, the memory node210(6) may aggregate the information from the other memory nodes (e.g.,sending memory nodes) that was identified by the respective memory nodeas satisfying the initial request for information, such as the dataidentified by the memory nodes that match the key.

In the example of FIG. 4, based on the internal packets received fromthe sending memory nodes, node controller of the memory node 210(6)generates an internal packet including information provided to it fromthe other memory nodes. The internal packet is provided external to thememory system 200 (as represented by arrow 428), for example, to aprocessor from which the memory system 200 received the external packetrepresented by the arrow 402. The internal packet provided by the memorynode 216(6) may include information from the memory system 200 thatcollectively satisfies the request for information, that is, informationrelated to the key of the external packet initially received by 210(1).

As illustrated by the example of FIG. 4, the memory system 200 maymanage operations internally responsive to an external packet receivedby the memory system 200. For example, memory nodes 210(1)-(N) of thememory system 200 may provide internal packets generated by a nodecontroller of the sending memory node to other memory nodes of thememory system 200. The internal packets may include information (e.g.,instructions and/or data) for the receiving memory node to performoperations to satisfy an operation associated to an external packetreceived by the memory system 200. At the completion by the memorysystem 200 of the operation associated with the external packet, anexternal packet may be provided by the memory system 200.

FIG. 5 illustrates a data structure 500 for a linked list data set thatmay be searched according to an embodiment of the invention. The datastructure 500 represents information linked together to form a largerset of data including information associated with keys “A,” “B,” “C,”“D,” “E,” “F,” and “G.” In particular, the data structure 500 includesdata subsets 510-570 linked together by pointers to form a larger dataset. Each of the data subsets 510-570 includes information associatedwith a respective key. A “head” of the data structure 500 is associatedwith data subset 510, which is located at address 0x1000 and includesinformation associated with a key “A.” A pointer 512 in the data subset510 points to data subset 520, which is located at address 0x1080 andincludes information associated with a key “B,” thereby linking the datasubsets 510 and 520. Likewise, subset 530 located at address 0x2000 andincluding information associated with a key “C” is linked to data subset520 by a pointer 522. Data subsets 540, 550, 560, and 570 at addresses0x0800, 0x3000, 0x4080, and 01100, and including information associatedwith keys “D,” “E,” “F,” and “G,” all respectively, are similarly linkedto data subset 530 and to one another by pointers 532, 542, 552, and 562that point from one data subset to another.

In a conventional system, to search the data structure 500 forinformation matching a search key “E,” a CPU, for example, sets acurrent search pointer to the head of the data structure 500 associatedwith the data subset 510 at address 0x1000. The CPU issues a memory readinstruction to read information from the current location identified bythe pointer and compares the information read from the current locationto the search key “E.” If the information read from the current locationmatches the search key “E,” then the search is completed and terminated.However, if the information from the current location does not match thesearch key “E,” the CPU advances the search pointer to a next location,which then becomes the current location.

As before, the CPU issues a memory read instruction to read informationfrom the (new) current location identified by the pointer and comparesthe information read from the current location. The steps of pointing toa new current location, reading information from the current location,and comparing the information to the search key “E,” is repeated untilthe information is found, or the entire data structure 500 has beensearched but no information is found, at which time the search isterminated. In the example data structure 500 of FIG. 5, the data subset550 includes information matching the search key “E.” As a result, theCPU will read information at data subsets 510, 520, 530, and 540, linkedtogether by pointers 512, 522, and 532, until reading the informationfrom the data subset 550 (linked by pointer 542) and determining thatthe information matches the search key “E,” at which time the CPUterminates the search.

In the example for the conventional system, the CPU is burdened withissuing the memory read instructions, comparing the information readfrom a current location to the search key, and terminating the searchupon completion.

FIG. 6 illustrates a flow diagram for searching the data structure 500for a memory system according to an embodiment of the invention. Thedata structure 500 may be searched for information based on the CPUissuing a single instruction to the memory system. The reading ofinformation from a current location and comparing the information to asearch key is managed internally to the memory system, in particular, bythe memory nodes of the memory system. For the purposes of the presentexample, each of the data subsets of the data structure 500 are storedby a respective memory node of a memory system including a plurality ofmemory nodes according to an embodiment of the invention, for example,the memory node 210 (FIG. 2) and/or the memory node 300 (FIG. 3).

At step 610, the memory system receives an instruction from the CPU forsearching the data structure 500 to find information matching a searchkey (e.g., search key “E”), beginning with the head of the datastructure 500, in particular the data subset 510 at address 0x1000. Atstep 614, the memory node, such as the memory node including the datasubset 510, performs a read operation of a current location identifiedby a pointer. At step 620, the memory node compares the information readfrom the current location to the search key. At step 624, if theinformation from the current location matches the search key, then atstep 630 the memory node generates an external packet including theinformation matching the search key and further including informationindicating that the information has been found. At step 634 the externalpacket is provided by the memory node to the CPU.

At step 624 if the information from the current location does not matchthe search key (e.g., search key “E”), it is determined at step 640whether the current location is the end (e.g., the last location) of thedata structure being searched. In the event the current location is thelast location, at step 644 the memory node generates an external packetincluding information indicating that no information matching the searchkey has been found. The external packet is provided by the memory nodeto the CPU at step 634. In the event the current location is not thelast location, at step 650 the memory node advances the search pointerto a next location to change the next location to the current location.At step 654, it is determined by the memory node whether the currentlocation is in the same memory node. If the current location is in thesame memory node, the memory node begins the process of readinginformation from the current location (step 614), comparing theinformation to the search key (step 620), and determining whether theinformation matches the search key (step 624).

If at step 654 it is determined by the memory node that the currentlocation is not in the same memory node, at step 660 the memory nodegenerates an internal packet that includes instructions to search forinformation matching the search key (e.g., search key “E”). The internalpacket is provided at step 664 to the memory node including the currentlocation. The memory node including the current location receives theinternal packet and begins the process of reading information from thecurrent location (step 614), comparing the information to the search key(step 620), and determining whether the information matches the searchkey (step 624).

In contrast to searching the data structure 500 using the conventionalsystem, in which the CPU is burdened with issuing all of the memory readinstructions, comparing the information from a current location to thesearch key, and terminating the search upon completion, the memory readoperations and comparisons are performed by the memory nodes within thememory system. From the time the CPU issues the initial searchinstruction to the time an external packet is provided to the CPU by thememory system, the CPU is free to perform other operations.

The memory system may include a plurality of memory nodes, wherein thememory nodes include local memory for storing information. The memorynodes may further include computational logic configured to performoperations on information, as well as include a node controllerconfigured to control operations within the memory node and generateinternal packets that may be provided to other memory nodes. Theinternal packets may include information for the receiving memory node,for example, instructions for operations to be performed by a receivingmemory node and/or data for the receiving memory node. Embodiments ofthe invention may be utilized to reduce the number of memorytransactions between a CPU and a memory system (e.g., processor 110 andmemory system 140 of FIG. 1), and additionally reduce the burden on theCPU for managing operations on information stored by the memory system.

From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

The invention claimed is:
 1. A method, comprising: receiving an externalmessage at a first memory node of a memory system, the external messageincluding a first instruction to perform a first memory operation;responsive to the first instruction, generating at the first memory nodea first internal message including a second instruction for a secondmemory operation, the second instruction not included in the externalmessage; providing the first internal message to a second memory node ofthe memory system; performing the second memory operation at the secondmemory node responsive to the first internal message; generating at thesecond memory node, a second internal message including at least one ofa third instruction or the second instruction, responsive to at leastone of the first internal message or the second memory operation,wherein the third instruction is not included in the external message;providing the second internal message to a third memory node of thememory system; and performing a third memory operation at the thirdmemory node responsive to the second internal message.
 2. The method ofclaim 1, further comprising performing the first memory operation at thefirst memory node.
 3. The method of claim 2, wherein the first memoryoperation at the first memory node comprises a read operation.
 4. Themethod of claim 1, wherein performing the second memory operationcomprises accessing a local memory of the second memory node.
 5. Themethod of claim 4, further comprising performing a computationaloperation at the second memory node on information read from the localmemory of the second memory node responsive to the second instruction.6. The method of claim 1, wherein a format of the internal message isdifferent than a format of the external message.
 7. The method of claim1, wherein the second internal message comprises information related tothe second memory operation.
 8. The method of claim 1, whereinperforming the second memory operation comprises performing a readoperation, a write operation, key search, addition and deletion ofinformation of a data structure, updating fields in a data structure, orcombinations thereof.
 9. The method of claim 1, wherein the first memoryoperation comprises searching for information related to a search key.10. A method comprising: receiving an external message at a first memorynode of a memo system, the external message including a firstinstruction to perform a first memory operation, wherein the firstmemory operation comprises searching for information related to a searchkey; responsive to the first instruction, generating at the first memorynode a first internal message including a second instruction for asecond memory operation, the second instruction not included in theexternal message; providing the second instruction to a second memorynode of the memory system; performing the second memory operation at thesecond memory node responsive to the second instruction; and accessing alocal memory of the first memory node to search for information relatedto the search key.
 11. The method of claim 10, wherein generating at thefirst memory node the first internal message includes the secondinstruction to search for information related to the search key.
 12. Themethod of claim 11, further comprising responsive to the first internalmessage, accessing a local memory of the second memory node to searchfor information related to the search key; generating a second internalmessage at the first memory node including information from the localmemory of the first memory node that is related to the search key;providing the second internal message to a third memory node of thememory system; generating a third internal message at the second memorynode including information from the local memory of the second memorynode that is related to the search key; and providing the third internalmessage to the third memory node of the memory system.
 13. The method ofclaim 12, further comprising generating a second external message at thethird memory node including the information from the first and secondmemory nodes; and providing the second external message external to thememory system.
 14. The method of claim 12, wherein information stored inthe local memory of the first memory node and information stored in thelocal memory of the second memory node are respective data subsets of alinked list data set.
 15. The method of claim 14, wherein generating thefirst internal message at the first memory node is responsive tocompleting a search of the data subset in the local memory of the firstmemory node for information related to the search key.
 16. The method ofclaim 12, further comprising comparing at the first memory nodeinformation read from the local memory of the first memory node to thesearch key.
 17. The method of claim 12, wherein accessing the localmemory of the first memory node comprises reading information stored bythe local memory of the first memory node.
 18. An apparatus, comprising:a processor; and a memory system configured to receive instructions fromthe processor to access information stored by the memory system; thememory system including a plurality of memory nodes, wherein each memorynode of the plurality of memory nodes is coupled to at least one othermemory node of the plurality of memory nodes by a communications networkand each memory node of the plurality of memory nodes is configured togenerate an internal message including instructions for an operationdifferent than the instructions received from the processor, theinternal message to be subsequently provided to another memory node ofthe plurality of memory nodes to perform the operation, wherein theother memory node subsequently generates a further internal message toforward to a subsequent one of the plurality of memory nodes.
 19. Theapparatus of claim 18, wherein each memory node of the plurality ofmemory nodes is configured to aggregate the information from othermemory nodes in the plurality of memory nodes to provide to theprocessor in response to the received instructions.
 20. The apparatus ofclaim 18, wherein the memory system comprises: a first memory node ofthe plurality of memory nodes configured to store information in a localmemory; and a second memory node of the plurality of memory nodescoupled to the first memory node of the plurality of memory nodes andconfigured to receive a first message that includes a first instruction,the second memory node of the plurality of memory nodes furtherconfigured to generate a second message that includes a secondinstruction not included in the first message and to provide the secondmessage to the first memory node of the plurality of memory nodes, thefirst memory node of the plurality of memory nodes further configured toperform a memory operation according to the second instruction.